1. Field of the Invention
The present invention generally relates to data processing techniques and, in particular, to a system and method for processing compressed audio data stored on a removable storage medium, such as a compact disc, for example.
2. Related Art
Many computer systems have the capability of receiving music data stored in compressed audio data files and of playing the music defined by the received audio data files. In this regard, these computer systems usually include a decompression application stored in the computer system""s memory. When the music defined by a compressed audio data file is to be played, the computer system invokes the decompression application, which decompresses the audio data file. After decompressing, the audio data file is compatible with conventional audio output devices capable of producing sound based on the uncompressed audio data.
Consequently, compressed audio data can be downloaded from the Internet, for example, and played by a user""s computer system. However, certain security issues arise pertaining to the transfer of audio data by computer systems. In this regard, most computer systems have the capability of not only playing the music downloaded from an external source, such as the Internet, for example, but also have the capability of copying the audio data. Therefore, it is possible to download audio data and to create many unauthorized copies of the audio data.
Unlike the computer systems described above, most portable compact disc (CD) players do not have the capability of decompressing audio data files. In this regard, portable CD players are designed to be small and lightweight to facilitate transportation and, therefore, do not include user interface devices (such as a mouse, a keyboard or a screen display) and/or other types of components for selecting and downloading decompression applications. It is possible to store decompression applications in the CD player during manufacturing of the CD player. However, due to the vast number of decompression techniques, storing decompression applications in the CD player during manufacturing could significantly increase the cost of the CD player. In this regard, additional ROM space may be added to the CD player to accommodate the decompression applications, or the decompression applications may be implemented in silicon. Each of these options increases the cost of manufacturing, and it would be desirable to avoid these costs, if possible.
In addition, even if decompression applications are stored in the CD players during manufacturing, compatibility with audio data files is not guaranteed, as the audio data files may be compressed via new techniques or via techniques incompatible with the decompression applications selected for storage. As a result, most portable CD players are not designed to decompress audio data. Instead, most portable CD players only process CDs having data stored in CD-DA (compact disc-digital audio) format, which is an uncompressed format. Consequently, the efficiencies pertaining to the storage of compressed data versus uncompressed data are not realized by most portable CD players.
Thus, a heretofore unaddressed need exists in the industry for providing a system and method of processing audio data such that security of the data can be enhanced and such that portable systems, such as portable CD players, can receive and process compressed data.
The present invention overcomes the inadequacies and deficiencies of the prior art as discussed hereinbefore. Generally, the present invention provides a system and method for processing compressed audio data stored on removable storage media.
The present invention utilizes a processing element, a system manager, and an audio output device. The system manager receives inputs from a user and, in response to the user inputs, reads organizational structure information stored on a removable storage medium, such as a compact disc, for example. Based on the inputs and the organizational structure information, the system manager identifies a set of compressed data stored on the removable storage medium. The system manager retrieves instructions of a decompression application from the removable storage medium and transmits these instructions to the processing element. The processing element executes the received instructions, thereby decompressing the set of compressed data into uncompressed data. The uncompressed data is transmitted to the audio output device, which produces sound based on the uncompressed data.
In accordance with another feature of the present invention, the organizational structure information includes at least one play list that indicates a correspondence between a plurality of songs defined by the data stored on the removable storage medium. When desired, the system manager retrieves these songs and includes these songs in the set of compressed data identified by the system manager.
In accordance with another feature of the present invention, a compiler is used to translate the instructions of the decompression application retrieved from the removable storage medium into a form compatible with the processing element. Therefore, the decompression application can be stored in a relatively high level to increase the number of processing elements that can execute the instructions of the decompression application. If desired, a dedicated processing element can be used to compile the decompression application.
The present invention can also be viewed as providing a method for processing compressed audio data stored on removable storage media. The method can be broadly conceptualized by the following steps: receiving a removable storage medium; receiving inputs form a user interface device; reading organizational structure information stored on the removable storage medium; retrieving a set of compressed data from the removable storage medium based on the inputs and the organizational structure information; retrieving a decompression application from the removable storage medium; decompressing the set of data via the decompression application to form an uncompressed set of data; and producing sound based on the uncompressed set of data.
Other features and advantages of the present invention will become apparent to one skilled in the art upon examination of the following detailed description, when read in conjunction with the accompanying drawings. It is intended that all such features and advantages be included herein within the scope of the present invention and protected by the claims.